Design and characteristics of included studies.

Objective
Anesthesia is correlated with the prognosis of cancer surgery. However, evidence from prospective studies focusing on breast cancer is currently limited. This systematic review aimed to investigate the effect of anesthesia-related interventions on oncological outcomes following breast cancer surgery in prospective studies.
Methods
Literature searches were performed from inception to June. 2023 in the Pubmed, Web of Science, Embase, and ClinicalTrials databases. The main inclusion criteria comprised a minimum of one-year follow-up duration, with oncological outcomes as endpoints. Anesthesia-related interventions encompassed, but were not limited to, type of anesthesia, anesthetics, and analgesics. The risk of bias was assessed using the Cochrane Risk of Bias Tool.
Results
A total of 9 studies were included. Anesthesia-related interventions included paravertebral nerve block (3), pectoral nerve block (1), sevoflurane (2), ketorolac (2), and infiltration of lidocaine (1). Cancer recurrence, metastasis, disease-free survival, or (and) overall survival were assessed. Among all included studies, only infiltration of lidocaine was found to prolong disease-free survival and overall survival.
Conclusion
Regional anesthesia and propofol did not improve oncological outcomes following breast cancer surgery. The anti-tumorigenic effect of ketorolac warrants future studies with larger sample sizes. Perioperative infiltration of lidocaine around the tumor may be a promising anti-tumorigenic intervention that can prolong overall survival in patients with early breast cancer.